The change in shape and color of hair is an important area of modern cosmetics. In this way, the appearance of the hair can be adapted to the current fashion trend and to the individual wishes of the individual consumer. The fashionable color design of hairstyles or the lamination of gray or white hair with fashionable or natural color shades is usually carried out by employing color-changing agents which permanently or only transiently, i.e., temporarily color the hair.
So-called oxidation coloring agents are used for permanent, intensive dyeings with corresponding fastness properties. Such coloring agents usually contain oxidation dye precursors, so-called developer components and coupler components. The developer components form the actual dyes under the influence of oxidizing agents or of atmospheric oxygen among each other or with coupling with one or more coupler components. The oxidation coloring agents are distinguished by excellent, long-lasting dyeing results.
For temporary dyeings, coloring or toning agents which contain so-called direct binders as a coloring component are usually used. These are dye molecules that are directly applied to the substrate and do not need an oxidative process to form the color. These dyes include, for example, the henna already known from antiquity for the dyeing of body and hair. In contrast to the dyeings obtainable with oxidation coloring agents, the dyeing results of temporary dyeings have a lower durability.
However, the keratin fibers dyed with the dyeing systems described above, in particular hair, have the disadvantage that they can change undesirably under external influences, for example, during or after hair cleaning.
“Unwanted change” is understood to mean the fading or bleeding, the loss of the color brilliance and the color shift of the hue of the hairs obtained by the respective dyeing. An undesirable change in the hair color usually occurs during or after the hair cleaning. The contact of the hair with water and surfactants, but also the massaging of the shampoo, the drying of the hair after the rinsing of the shampoo, or blow drying during the subsequent drying process can adversely affect the adhesion of the hair dye and can lead to an undesired color change and/or to less brilliance of the hair color. The undesirable change caused can be additionally amplified as a result of further environmental influences and/or sun effects.
EP 1676604A1 describes a method for improving the hue of hair in which the hair is first washed with a shampoo which, in addition to an anionic surfactant and a special silicone, contains at least one water-soluble salt, preferably sodium sulfate. In a second step, the hair is treated with a conditioning agent comprising a higher alcohol and a cationic surfactant in a specific weight ratio and then rinsed out.
However, the methods known in the prior art do not always lead to the desired color retention, in particular the reduction in the color shift.